Anthony Torres, serving a life sentence for murder, sits inside his Security Housing cell. At 48, he's studying for his high school equivalency certificate, and a teacher gives him tests from outside his cell door.

The metal door swings open into Security Housing Unit B at the California State Prison, Sacramento, one of four prisons in the state with such units.

Photo: Michael Macor, The Chronicle

The metal door swings open into Security Housing Unit B at the...

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Above: Former inmate Steven Czifra, 39, now an English major at UC Berkeley, is an outspoken critic of the solitary units.

Photo: Michael Macor, The Chronicle

Above: Former inmate Steven Czifra, 39, now an English major at UC...

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Left: Inmates in the Security Housing Unit have a narrow window in each cell through which to view the outside world.

Photo: Michael Macor, The Chronicle

Left: Inmates in the Security Housing Unit have a narrow window in...

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48-year-old Anthony Torres, who is serving a life sentence for murder is escorted back to his cell by a corrections officer at security housing unit B at the California State Prison Sacramento on Wednesday March 05, 2014, in Represa, Calif. Sacramento is one of four prisons in the state that have Security Housing Units. Critics argue that the SHU's are solitary confinement and torture.

Photo: Michael Macor, The Chronicle

48-year-old Anthony Torres, who is serving a life sentence for...

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The top and bottom tiers of security housing unit B at the California State Prison Sacramento on Wednesday March 05, 2014, in Represa, Calif. Sacramento is one of four prisons in the state that have Security Housing Units. Critics argue that the SHU's are solitary confinement and torture.

Tucked within the sweeping green hills here is one of California's high-security prisons, and within it a cellblock for the worst of the worst inmates, where a visit requires a protective vest and three authorization checkpoints.

The segregation unit at California State Prison, Sacramento, houses convicts removed from the general population because they've committed crimes while incarcerated or are affiliated with notorious prison gangs that prison officials say control drugs and violence on the streets.

Inmates here spend nearly entire days inside 80-square-foot concrete cells. The few freedoms afforded to prisoners in the general population - such as handcuff-free time in an open yard under an open sky - are mostly stripped away.

Here, they eat in their cells, their food slipped through a slot. They get no phone calls, except in emergencies. Visits with family and friends are strictly no-contact. Social interactions, even with other inmates, are limited to nonexistent.

Critics call this solitary confinement. Prison officials use the term Security Housing Units.

Regardless of what it's called, critics argue that the treatment inmates receive in these units borders on torture. The sensory deprivation that occurs when inmates are isolated for years or decades inevitably results in long-term mental health issues, critics say.

And here's why you should care, a Bay Area lawmaker points out: Each month, around 23 inmates are paroled from the segregated units into communities throughout the state.

"My concern is what happens to people who are released from these conditions of deprivation of other human contact or activities," said state Sen. Loni Hancock, D-Berkeley. "To me, that seems like something every community in California should be concerned about."

Officials' reasons

Prison officials say it's necessary to segregate some of the state's 134,000 prisoners to ensure the safety of staff and other inmates and to limit the reach prison gangs have on drug trafficking and violence in California communities. But in hearings at the state Capitol over the past five months, California Department of Corrections and Rehabilitation leaders acknowledged that their policies have isolated too many inmates for too long.

"I think we all agree that it was far too easy to get in and too hard to get out," said Martin Hoshino, undersecretary of operations at the California Department of Corrections and Rehabilitation.

One hundred six of the 3,600 segregated inmates had spent at least 15 years in the special unit as of July. Twenty-three inmates had served at least 25 years.

Now the department is transferring hundreds of prisoners out of the segregated cells as part of a 2012 pilot program that they hope to make a permanent policy next month.

"How is this not solitary confinement?" asked Steven Czifra, 39, a student at UC Berkeley and a former prisoner who served a total of 10 nonconsecutive years, including two stints totaling 3 1/2 years in segregated cells, after a carjacking conviction, an in-prison battery conviction and multiple parole violations. "Because you can call to someone through a ventilation chamber? Every part of it is to break you down."

Czifra says he has anxiety, nightmares and irrational mood swings that he attributes to his time in isolation.

Anger, frustration

Last summer, more than 30,000 inmates refused solid food during a hunger strike over the use of the segregated cells. It was the third hunger strike since 2011 by inmates who say the state needs to heed research about the long-term mental and physical impacts of prolonged isolation.

Inmates expressed anger and frustration not just with the conditions, but also with why they were sent there and how long they've had to stay.

"The whole process is kind of bogus," said Anthony Torres, 48, a segregated inmate at California State Prison, Sacramento, who agreed to an interview last week from inside a shielded and metal-meshed cell with just enough room for him to stand.

Torres was convicted in 1997 for his role in multiple homicides and has spent most of his life sentence in a segregated cell after he was validated as a gang associate. He said he takes advantage of programs offered to the segregated inmates at the Sacramento prison. A teacher comes to his cell door to administer tests for his GED high school equivalency program.

Torres and another segregated inmate, Fred Jones, who also agreed to an interview, described Sacramento as a step up from other state prison segregation units, particularly the one at Pelican Bay in Del Norte County, due to Sacramento's incentive programs.

'Extreme' danger

But Correctional Lt. Bryan Donahoo said that Torres is closely tied to a prison gang, and that to believe prison gang members and their associates don't control drugs and violence on the street "is naive."

"These inmates are extremely dangerous," Donahoo said after exiting from the dark segregated unit into a sun-drenched prison yard anchored by a baseball diamond and populated by wandering geese.

Of the 3,600 prisoners housed in segregation cells, about 2,200 of them are there for being gang members and associates, according to data from the corrections department.

An inmate who commits a violent offense in prison, such as murder, can land in the segregation unit for up to five years. Gang members and associates, however, receive indeterminate terms. Their cases are reviewed every six years unless they participate in a four-year "step-down" program that includes keeping a journal.

The step-down program is part of the corrections department pilot program that prison officials hope to adopt as their new policy. It's described as a behavior-based program where inmates can demonstrate a "willingness and commitment to discontinue gang activity" while in prison.

Changing rules

Still, advocates and family members have poured into legislative hearings in Sacramento to demand changes in how the corrections department validates inmates as gang members.

"Under the prior policy, all it took was one activity," said George Giurbino, a former prison warden who is leading the review of the department's segregation policies. "If an individual's name was found under an inmate's pillow 200 miles away, that would bring him back to a security housing unit."

Giurbino said the proposed policy creates additional requirements to validate an inmate as a gang member or associate who should be housed separately from the general population. As part of the pilot program, prison officials are reviewing inmates placed in segregation units for gang ties.

Of the 632 inmates isolated for being gang associates whose cases have been reviewed so far, 408 have been sent back to the general prison population or are on their way, said corrections spokeswoman Terry Thornton. An additional 185 inmates are in the step-down program, Thornton said.

"That simple fact speaks for itself," said Hoshino, the prisons' undersecretary of operations. "It is not something we are planning to do or talking about doing. It's actually happening."

At a legislative hearing last week, Hancock and Assemblyman Tom Ammiano, D-San Francisco, both chairs of the public safety committees in their respective chambers, said they will continue to look closely at prison segregation policies.

Ammiano introduced legislation that would place a three-year cap on the term in segregated units for reasons such as gang membership. Hancock is planning to introduce legislation as well.